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Nago, Makito*; Motoshima, Takayuki*; Miyakawa, Kazuya; Kanie, Shunji*; Sanoki, Satoru*
Proceedings of ITA-AITES World Tunnel Congress 2017 (WTC 2017) (USB Flash Drive), 10 Pages, 2017/06
This study presents a new approach to increase construction safety under methane inflow conditions by providing the three-dimensional concentration distribution of methane in underground structures. The study was conducted at the Horonobe Underground Research Laboratory, which is located in Neogene sedimentary rock where groundwater contains dissolved methane. As conventional gas sensors are confined to measurement at a single point in time and space, a new system was developed combining a laser methane detector and a laser range finder to effectively obtain the spatial concentration distribution of methane. This system was tested in tunnel galleries located at a depth of 350 m. The results show that this system is effective for identifying unpredicted methane emissions as well as predicted emission hotspots and for examining the validity of the ventilation scheme, which ensures construction safety.
Sato, Masaru*; Kinoshita, Naoto*; Sugawara, Kentaro*
JNC TJ7430 2005-002, 81 Pages, 2000/03
JNC-TJ7430-2005-002.PDF:56.19MB
no abstracts in English
Ijiri, Yuji*; Nago, Makito*; Kinomura, Koji*; Sugihara, Yutaka*; Shigehiro, Michiko*; Sato, Masaru*; Kunimaru, Takanori
no journal, ,
This paper presents the in-situ measurement data and the results of simulation analyses in order to develop technologies for monitoring rock behaviors using tiltmeters placed near ground surface. From the data, it is shown that the tiltmeters are able to capture the rock behaviors due to shaft excavations and concrete placements and are very sensitive to capture earthquakes, change in barometrical pressure and tide as well as the movements of heavy-construction-equipments. The applicability of inverse analysis for identifying the rock properties using tilting displacement data associated with construction activity is demonstrated by elastic analyses. In addition, the applicability of tiltmeters for monitoring high-permeable zones is also demonstrated by Hydro-Mechanical coupling analysis, because the groundwater flow toward the shaft along high-permeable zone cause an increase in the rate of tilting displacement and change in displacement mode.
Abe, Hironobu; Shimoyama, Tadashi; Yamasaki, Masanao*; Sanoki, Satoru*
no journal, ,
no abstracts in English
Motoshima, Takayuki*; Shirase, Mitsuyasu*; Sanoki, Satoru*; Miyakawa, Kazuya
no journal, ,
Release of methane gas from sedimentary formations is often reported during excavation or operation of tunnels. Detecting methane gas, an odorless and colorless gas, is an important safety issue during construction and operational phases as it is explosive when mixed with air. This paper presents an approach to detect methane gas by integrating a laser methane detector into a 3-dimensional laser scanning system, including the system setup, performance of the system in the field, data implementation, and data visualization method. The system was tested at the underground research laboratory located at a depth of 350 m in sedimentary formations.
Yahiro, Hanae*; Motoshima, Takayuki*; Sanoki, Satoru*; Miyakawa, Kazuya
no journal, ,
no abstracts in English